NMM ontology: Add writeback on nmm:performer and nmm:musicAlbum
NMM ontology: Add writeback on nmm:performer and nmm:musicAlbum

Add tracker:writeback annotation on the two properties nmm:performer and
nmm:musicAlbum.

outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker,hoheinzollern/tracker,hoheinzollern/tracker,outofbits/tracker,hoheinzollern/tracker,outofbits/tracker,outofbits/tracker